MALABSORPTIVE DISORDERS
DEFINITION:
A group of disorders caused by the defective absorption of
ingested nutrients characterized by abdominal distension,
malabsorption & steatorrhea, muscle wasting, and failure to thrive.
EPIDEMIOLOGY:
PATHOGENESIS:
- defective absorption of ingested fats, proteins, CHO, and/or
minerals by whatever mechanism results in various deficiencies
- the clinical features of congenital disorders affecting only a
single specific intestinal transport process (i.e.,
abetalipoproteinemia) are different from those of generalized
malabsorptive states
- must rule out children with chronic renal disease or
intracranial lesions
DIFFERENTIAL DIAGNOSIS*:
- Chronic Pancreatitis
- Cystic Fibrosis
- Shwachman's Syndrome
2. Inadequate Penetration of the Unstirred Water Layer
- Biliary Atresia
- Cholestatic States
- Giardiasis
2. Intestinal Disorders
- Short Bowel Syndrome
- Stagnant Loop Syndrome
2. Mucosal Injury Disorders
- Celiac Disease
- Chronic Malnutrition
- Chronic Persistent Diarrhea
- Immunodeficiency States
- Immunoproliferative Small Intestinal Disease
- Intractable Diarrhea of Infancy
- Postenteritis Syndrome
- Tropical Sprue
- Whipple's Disease
- Wolman Disease
3. Impaired Postenterocyte Event
- Intestinal Lymphangiectasia
CLINICAL FEATURES:
- weight loss
- anemia
- diarrhea
2. Symptoms Related to Malabsorption
- abdominal distension/tenderness
- diarrhea
- flatulence
- failure to thrive (FTT), short stature
3. Symptoms Related to Secondary Deficiencies
- muscle wasting (proximal muscle groups)
- edema
- hypopituitarism -> amenorrhea
2. Fat Malabsorption
- pale, soft, bulky, malodorous stools
2. Vitamin D Deficiency
- calcium and magnesium deficiencies
- bony pain, tetany, osteomalacia, paresthesia
3. Vitamin E Deficiency
4. Vitamin A Deficiency
- night blindness, xerophthalmia, follicular
hyperderatosis and dermatitis
5. Vitamin K Deficiency
- bleeding tendency, bruising, purpura
3. Other Malabsortion
- sore tongue, angular stomatitis, anemia
2. Iron Deficiency
INVESTIGATIONS:
- output vs input
- excretion should not be >15% of intake in infants
- excretion should not be >10% of intake in children
2. Screening Tests
- fecal fat content
- fasting serum carotene concentration
- 14C-triolein absorption
2. Carbohydrate Malabsorption
- hydrogen concentration in expired air after an oral dose
of sugar (2g/kg body weight to max of 50 g) and abnormal if >
20 ppm during the first 2 hours
2. Screening Tests - Stool
- for reducing substances (Clinitest)
- for pH < 6.0 (organic acids produced by bacteria on
unabsorbed sugars)
3. Protein Malabsorption
- abnormal test if > 0.8% of IV injected dose excreted in
the stools over 4 days
2. Fecal Clearance of Serum Alpha-1-Antitrypsin
- abnormal test if > 15cc/day excreted on a 48 hour stool
collection
4. Hematology
- calcium, magnesium, phosphate, iron, folate, vitamins D,
E, A, K, albumin, liver function tests
2. RBC smear
- for anemia (micro/macrocytic), or acanthocytes (abetalipoproteinemia)
3. Schilling Test
5. Microbiology
- stool for giardia lamblia
- jejunal or duodenal aspirates for bacterial overgrowth
6. Imaging Studies
- to rule out statis
- malrotation
2. Abdmonial Ultrasound
- pancreatic masses, biliary tree anomalies, stones
7. Biopsy
- mucosal structure
- disaccharidase deficiencies
MANAGEMENT
- treat underlying disorder
- fat soluble vitamin supplements
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